Lightning arrester



. Feb. 12 1924. 1,483,540

c. T. ALLCUTT LIGHTNING ARRESTER Filed May 12, 1919 WITNESSES: INVENTOR PatentedFeb. 12, 1924.

UNITED STATES PAT r rsics.

GHESIER T. .ALLCUTT, OE PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELEGTEIC & MANUFACTURING COMPANY, A CORPURATIQN F PENIQ'SYLVANIA.

LIGHTNING ARRESTER.

Application filed May 12,

To all whom it may concern Be it kn ivn that I, Cnnsrnn T. ALLcUr'r, a citizen: of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Lightning Arresters, of which the following is a specification.

l\'ly invention relates to spark-gap electrodes and particularly to apparatus of this character, as employed in lightning arresters.

in the accompanying drawings, Fig. 1 1s a sectional view of a spark-gap device constructed in accordance with my invention; Pigs. :2, 3 and 4 are slight modifications thereof.

l leretofore, it has been customary to construct spark-gap electrodes of a metal, such, for example, as brass, which has the propof requiring a relatively high voltage to maintain an are between the two electrodes so constructed. The advantage of using electrodes of this character, in prefer-- ence to inetals not possessing this property,

is that a smaller number of gaps, connected rice, is required to suppress a power are .ing an overvoltage discharge. y my invention, I provide spark-gap elects .{les composed of a material which is a v: "cod electrical conductor at relatively unperatures and a very good insulator tively higher temperatures so that, lischarge occurs between two spaced the particular point at which the e leaves and enters the electrodes be heated thereby and immediately cl considerably higher resistance, serving to break down the discharge ov'envoltage still exists on the line, to it to seek a new discharge path. This s in a particularly effective suppresoi on are between two electrodes of the le crihcd. ff hotter understanding of my invenrcference may now be had to the acianying drawings in which l show a osing' 1 provided with an insulating 1 end containing a material 3 which constitutes one of my electrodes and may be composed of lead pcroxid preferably comh d with some inorganic hinder, such as silicate. similar electrode 4 com- 91' similar material is attached to the 1919. Serial 296,35;

cover member 2' by means of s conducting member 5 extending therethrongh. The electrode l is connected to a line 6 through a terminal 7 and the casing 1 is connected to ground 8 by means of a terminal 9.

Fig. 2 is a modification of my invention in which two electrodes 10 and 11 are connected to a line 12 and ground 13, respectively, and which are provided with coatings of lead peroxide or some material of similar prop-- erties. The electrodes 10 and 11 are mounted upon metellic supports 14 which, in turn, are mounted. upon a common insulating base Fig. 3 shows another modification of my invention in which a body of lead p-eroizid 16 is disposed within a cup shaped member 17 and may be the form of a powder. The other electrode 18 is a metallic plate This form of my invention is particularly suitable for direct current, under which conditions the lead peroxid should be made the cathode.

Fig. 4e shows still another modification of my invention in which two horn-gap elec trodes 19 and 20 are each provided with a coating hi of lead peroirid.

From the foregoing description of my in vention, it will he obvious to those skilled in the art that any small discharge of current between the electrodes will he carried thereby without producing any change in the lead peroxid on account of relatively small amount of heat generated thereby, while, with a relatively heavy discharge of current, the heat generated thereby will immedieteiy transform the lead peroxid into a lower oxid of relatively poor electrical conductivity, thus increasing the resistance of the path oi the discharge. Eventually, the resistance of the path will become such that the voltage will he insuiiicient to maintain a discharge therethrough and either the discharge will he broken thereby or s new discharge path will he found, if the voltage is still sufficiently above normal.

It will be understood that, for line voltages higl'ier than the maximum on which single grep ll function ei'i'ectively, two or more oi the netu're described may he employed and connected in series relation. Wide ii l ve escribed my invention in a plurality o n it will lceohvious to those l 1 it is not limited to those set forth but is susceptible of various minor changes and modifications without departing from the spirit thereof and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or are specifically set forth in the appended claims.

I claim as my invention:

1. A discharge-gap member comprising a conducting member provided with a coating of conductive oxid which becomes converted by heat into a difierent oxid of higher electrical resistance.

2. A discharge-gap member comprising a conducting member provided with a coating of a metal compound which becomes converted by heat into a compound of high resistance.

3. A discharge-gap member comprising a conducting member provided with a coatingof a metal compound of low-heat con ductivity and low electrical resistance which becomes converted by heat into a compound "of different chemical composition and high electrical resistance.

4-. A discharge-gap member comprising a conducting member provided with a coating of lead peroxid.

5. A discharge-gap member comprising a. conducting member provided with a coating of material comprising lead peroxid and a binder.

6. A discharge-gap member comprising a conducting member provided with a coatin of material comprising lead peroxid an sodium silicate.

7. A lightning arrester comprising a plurality of spaced dischar e members, one of said members being provided with a coating of lead peroxid.

8. A lightning arrester comprising two spaced discharge members, one of said memhere being connected to a source of supply and the other being connected to ground and provided with a coating of lead peroxid.

9. A lightning arrester comprising two spaced discharge members, each provided with a coating of lead peroxid.

In testimony whereof, I have hereunto subscribed my name this 24th day of April,

CHESTER T. ALLCUTT. 

